fix improper size calc

src/wallet/wallet2.cpp

@@ -6236,6 +6236,9 @@ std::string wallet2::make_background_keys_file_name(const std::string &wallet_fi
 //----------------------------------------------------------------------------------------------------
 bool wallet2::parse_long_payment_id(const std::string& payment_id_str, crypto::hash& payment_id)
 {
+    if (payment_id_str.size() != 64)
+    return false;
+
   cryptonote::blobdata payment_id_data;
   if(!epee::string_tools::parse_hexstr_to_binbuff(payment_id_str, payment_id_data))
     return false;
@@ -15113,6 +15116,7 @@ bool wallet2::parse_uri(const std::string &uri, std::vector<uri_data> &data, std
     }
     else if (kv[0] == "tx_payment_id")
     {
+      // standalone payment ids are deprecated. use integrated address
       crypto::hash hash;
       if (!wallet2::parse_long_payment_id(kv[1], hash))
       {